21251041 has 4 divisors (see below), whose sum is σ = 24286912. Its totient is φ = 18215172.

The previous prime is 21251023. The next prime is 21251053. The reversal of 21251041 is 14015212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21251041 - 2¹⁹ = 20726753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21251141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1517925 + ... + 1517938.

It is an arithmetic number, because the mean of its divisors is an integer number (6071728).

Almost surely, 2^21251041 is an apocalyptic number.

It is an amenable number.

21251041 is a deficient number, since it is larger than the sum of its proper divisors (3035871).

21251041 is an equidigital number, since it uses as much as digits as its factorization.

21251041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3035870.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21251041 is about 4609.8851395669. The cubic root of 21251041 is about 276.9874357319.

Adding to 21251041 its reverse (14015212), we get a palindrome (35266253).

The spelling of 21251041 in words is "twenty-one million, two hundred fifty-one thousand, forty-one".